Signaling



March 3, 1931." I w, RUNGE I 1,794,645

SIGNALING Filed July 6, 1929 AMPLIFIER UUW INVENTOR WILHELM RU E BYv-7 We-A,

ATTORNEY Patented Mar. 3, 1931 mmnew 3 mm:

wrnnntivr nUNeEQonBnBtIiv,ferns-MANY, mam T0 rnnnnuivxnivensnnnscnnrm nun DRAHTLOSE TELEGBAPHIE M. B; 3., otjnnnnrn. GERMANY, A conPonArIoNj,

OF GERMANY std Manned Application fi ledluly 6, 1929, Serial No. 376324, main Germany July 1928.

it is knownthat the suppression of the carrier-frequency in transmitters'for wire less telephony has a number of advantages as compared with normal telephony with carrier-frequency. An important advantage is the saving of the energy otherwise radiated f out with the carrier-frequency. ;However, the suppression of the carrier-frequency has.

considerable disadvantages also.v These are: a considerable complication of the sender as compared with the'simple carrierstelephony and, the fact that the transmission cannot be heard without 7 suitable special receivers Working with the addition of a carrier wave.

According to theinvention, both disadvantages are eliminated, not by suppressing the amplitude of the carrier-frequency, but

7 by reducing it to a small fraction of its normale value. l/Vith normal carrier telephony and 100% modulation, the amplitude of the side band is one-quarter; of the carrier amplitude. Since this value must only be reached for the peaks, to'avoid over-modulation, one has worked so far with a mean degree of modulation amounting to about 30%.

In this case the side band amplitude amounts to /3 of the carrier current amplitude; or in other words, the carriersourrentis six times as strong as the side band amplitude.

the carrier current amplitude from that value to the order of magnitudeof the mean carrier-frequency amplitude, takes place. This can be accomplished most simply by lmeans at the transmitter and the transmitted communication is very well heard even with simple receivers. The energy contained in the reduced carrier then amounts to only a few. percent of the value with ordinary carrier telephony. Therefore, the greater part of the energy radiated out with the carrier in normal carrier telephony can i be saved by this simple method or else be used fortheside bands.

Fig. 1 of the accompanying diagram, and, the filter arrangementshown in Fig. 2 of the drawing. 7

According to the invention a reduction of In Fig. 1, twotubes, l andQ, worlr iii-phase opposition. Theirgridsjare coupled by the coil 3, fr0m there a branch leads over coil which isconnected with the, cathode over the anodic voltage supply i I igh frequency energy is aconveyedto the a '1 system through the input circuit 8;-' thisj Y causes a high frequency'voltage at the winding 4 and therefore at both grids. Since this high frequency voltage is co-phasalonbothv grids, the effect ofboth anode currents, in-

. duced from the coil'6 in the output circuit 9, is neutralized. If modulation voltages,

for example voice currents are fed to thesystem over theinput circuit 10, the coil of which induces currents in the coil3, both V grids are influenced with low frequency in push-pull 'fashioniand' the equilibrium be tween the two tubes is disturbed. The side J 'bandfrequencies jthusproduced are trans ferred to the' output circuitj9,

The suppression of thecarrier wave :re- I quires a far-going symmetry of'the conneci tions, equal position'of the tubecharacter- I istics, etc., the construction of: which is.eXj-- ce'edingly diflicult. j H y J Accordingto the invention the equilibrium of the. system isdisturbed additionally witlrf "out considering sma 'll asymmetries, ifor eX-.. ample, by adding to thegridcircuit a stopper cirouit in tune with thelhigh frequency fed at 8, which reduces the high frequenCyam .plitude conveyed to this grid I compared with the other. Thus the anodic alternating.cur:-

rentsof tube 1 and tube, 2 are'ditferent from; u each other. Thelcurrent induced inthe output circuit 9 is'broughtto about the same amplitude that the side "bands have on the average. Since the equilibrium is purposelyv muchfdisturbed, to obtain a carrier balance desirable for intelligibility, exact balancing ofthetubes andgood symmetry of the connections require no further attention.

To carry out the proposed procedure, the following method is also suitable. By means of the modulation voltage (voice currents for example) an auxiliary frequency is modulated first, With this the transmitter proper is modulated and the band-pass filters are thus arranged so that the carrier-frequency is separated out. 7

The filter chains necessary to separate the carrierfrom the side bands are constructed more simply, however, that is, With a smaller number of units. Here also the arrangement is much simpler than is necessary forcomplete suppression smcemuch less is requlred,

from the filter chains and therefore the construction is simpler.

In carrying into practice this method of first modulating an auxiliary frequency with the modulator energy, recourse may be had to a circuit arrangement according to Figure 2. In a composite or mixing? tube M1 the oscillations generated by the intermediate-frequency oscillator G1 are modulated by the speech currents generated by the microphone T. A filter arrangement F1 is provided to partly suppress the carrier wave.

The intermediate-frequency carrier Wave serves for the modulation of the radio tre quency oscillations generated by' the generator G2 in another composite tube B2. The carrier Wave of this generator as Well as sideband energy are separated in another filter circuit F2.

Since the filter F1 may have also a certain permeability for the carrier Wave, it need not,

of course, comprise as many units or meshes oscillatory energy to each of the control elec-' trodes in parallel, and means comprising a tuned circuit in series with only one of the control electrodes and the polarizing means for preventing the equal application of oscillatory energy to the control electrodes of the devices.

r V 3. In undulating electrical current ap- V .paratus the combination of a pair of electron electrodes in parallel, means'jcomprising a tuned circuit in series With only one ofthe control electrodes and the polarizing means for preventingthe equal application of oscillatory energytothe control electrodes of the devices,'means for applying alternating: energy'to the control electrodes ofthe devices in series, means for amplifyingthe output of the devices, and. meansfor electromagnetically transmitting the amplified output of the electron discharge devices.

WILHELM RUNGE.

as a filter serving the purpose to pass only; i

side-band energy unobstructedly. Hence, the filter scheme required inconnection With the present invention may consist-0f a lower r number of units. 7

I claim as my invention:

1. In undulating electrical current apparatus the combination of a pair of electron discharge devices, means, for coupling the anodes of the devices together, means for cou-' pling the control electrodes of the devices together, means for polarizing the control electrodes of the devices to substantially the same potential Value, means for supplying. oscil5 latory energy to each of the control electrodes in parallel, and, means 'comprisingan impedance in series with only one of the 'control electrodes and the polarizing means for preventing the equal application. of oscil latory energy to the control electrodes of the devices. i V

2. In" undulating electrical current apparatus' the combination'ofa pair ofelectron V discharge devices, means for coupling the anodes of the devicestogether, means for.

coupling the control electrodes or the devices togetherpmeans for polarizing the control electrodes of the devices to substantially the same potential value,.means.for supplying V 

